A vehicle transmission delivers mechanical power from an engine to the remainder of a drive system, such as fixed final drive gearing, axles and wheels. To operate efficiently, the vehicle transmission is typically lubricated with a lubricant, such as oil. The transmission may be coupled to a transmission auxiliary oil pump (“TAOP”), which pumps the lubricant from a source to the transmission.
The TAOP is powered by a motor, such as an alternating current (“AC”) motor, which may be supplied with a current via a voltage source inverter. The particular magnitude of current provided to the motor depends on an amount of oil that is needed by the transmission, the viscosity of the oil, the specific operating temperature of the oil, or a desired oil flow rate. Typically, the motor is also electrically coupled to a DC bus, which provides a voltage to counter unwanted effects of a back electromagnetic flux (“EMF”) that may be produced if the voltage source inverter provides a current magnitude that exceeds maximum torque limits of the AC motor.
Although the aforementioned TAOP generally operates adequately, it may be improved. For example, as mentioned above, the AC motor may be configured to operate up to certain maximum torque limits; however, in some cases, it may be desirable to maintain motor operation below the maximum torque limit and to prevent a torque overload on the motor. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.